Lucroy, a two-time All-Star catcher, joined Texas last season after a trade-deadline deal with the Milwaukee Brewers.
The deal was announced Sunday while the Rockies were playing the second game of a day-night doubleheader against Washington. Colorado has a solid lead for an NL wild-card spot.
Lucroy was a key cog in the Rangers’ postseason run in 2016, helping the team achieve the American League’s best record. He hit 11 homers and batted .276 during the stretch.
His production has slipped this season, as he is hitting .242 with only four homers.
Lucroy’s play behind the plate remains solid, having made 65 starts at catcher this season. He has thrown out 13 of 44 would-be basestealers this year, and has caught a major league-most 159 runners trying to steal since 2011.
Monday is the deadline for teams to make trades without waivers.
ESPN’s Jerry Crasnick and The Associated Press contributed to this report.